hasNext

Returns true iff I have more elements
when traversed in the forward direction.
(In other words, returns true iff
a call to ShortListIterator.next() will return an element
rather than throwing an exception.

hasPrevious

Returns true iff I have more elements
when traversed in the reverse direction.
(In other words, returns true iff
a call to ShortListIterator.previous() will return an element
rather than throwing an exception.

add

Inserts the specified element into my underlying collection
(optional operation).
The element is inserted immediately before the next element
that would have been returned by ShortListIterator.next(), if any,
and immediately after the next element that would have been
returned by ShortListIterator.previous(), if any.